In a collision involving a vehicle, such as an automobile, particularly in a serious head-on collision, the steering column that operatively couples the steering wheel assembly to the steering gear assembly and the axle for the front wheels, for example, may be forced into the passenger compartment of the vehicle due to the deformation of the front of the vehicle body. In order to avoid serious injuries to the operator of a vehicle resulting from the steering column being forced into the passenger compartment, steering columns have been proposed that are constructed in two parts capable of moving axially relative to one another. In a collision, therefore, such two-part steering columns can accommodate significant deformation of the front portion of a vehicle body without significant movement of the column into the passenger compartment.
In one type of a two-part steering column, one part of the column is hollow and has a larger diameter than the other part. Upon the application of an axial impact load, the part of the column having the smaller diameter telescopes into the part having the larger diameter. Such a two-part steering column is described and illustrated in Bogosoff et al. U.S. Pat. No. 3,394,612, for example.
In another type of a two-part steering column, the two parts of the column are separated and the resulting gap is bridged by a shock absorbing element. Two part steering columns of the second type are described and illustrated in Orlich et al. U.S. Pat. No. 3,482,466, German Patentschrift No. 1,298,010 and German Auslegeschrift No. 1,655,581. In a particular embodiment of a two-part steering column that includes an intermediate shock absorber portion, the opposite ends of the column are coupled to the steering wheel shaft and to a steering gear assembly by joints, such as universal joints, that are relatively torsion-stiff. During a frontal collision, the steering column deforms into a lightning-like shape. The construction of such a steering column is described and illustrated in the bi-weekly German magazine "Mot", at pages 50 and 52 of the Oct. 19, 1968 issue.